The information technology manufacture now provides a mother board with a wake-up function, such as Wake-up On LAN technology (WOL) or advanced management technology (AMT). A power of the mother board with the wake-up function is provided by a power supply having a system module and a standby module, and the power supply for example is an Advanced Technology eXtended (ATX) power supply. When the user turns off the computing system, the system module of the power supply is turned off without providing the system voltage to the mother board, but the standby module of the power supply is still turned on, such that the standby module is able to provide a standby voltage to the mother board for waiting to receive a wake-up signal. Once the mother board receives the wake-up signal, the computing system will be turned on soon.
Referring to FIG. 1, FIG. 1 is a block diagram of a conventional power supply. The conventional power supply 1 is used in a computing system for providing a power to the mother board. The conventional power supply 1 includes an AC rectification block 11, a system module 12, and a standby module 13. The AC (alternative current) rectification block 11 receives an AC (alternative current) power from an AC (alternative current) power supply source 2 electrically coupled thereto, and thus outputs a DC power to the system module 12 and the standby module 13. The AC rectification block 11 is further used to adjust the power factor of the DC power.
The system module 12 outputs a plurality of voltages such as +12V, +5V, and +3.3V. The system module 12 is substantially a DC/DC converter or a switched power supply module, which includes a system switch block 121, an isolation transformer 122, a system output block 123, and a system feedback block 124.
The DC power is inputted to the isolation transformer 122 and the system switch block 121. The primary winding of the isolation transformer 122 is electrically coupled to the AC rectification block 31 and the system switch block 121 respectively. The system feedback block 124 is electrically coupled between the system switch block 121 and the system voltage (+5V). The system output block 123 electrically coupled to the two ends of the secondary winding of the isolation transformer 122, and outputs the system voltages (+12V, +5V, and +3.3V) to the mother board.
The composition and function of standby module 13 is similar to system module 12 expect the output voltage. The outputted voltage of the standby module 13 is single for providing standby voltage, such as +5V (SB5V), to the wake-up module of the mother board.
It is noted that the system module 12 is turned on when the computing system is turned on, but is turned off when the computing system is turned off. The standby module 13 is turned on even when the computing system is turned off, such that the computing system is able to be wake-up when a wake-up signal is used to trigger the wake-up module of the mother board. Even when the computing system or the mother board is not used to support the wake-up function, the standby module 13 still provides the standby voltage, and thus the unnecessary power consumption is increased.
Currently, more and more people take care of the environmental protection issue, and most countries are dedicated to reduce the unnecessary power consumption. To save the power, the user must pull the plug of the power supply or switch the on/off bottom of the conventional power supply to turn off the standby module, and thus it is inconvenient to the user.